提出 #36973858

---

ソースコード 拡げる

#![allow(unused_imports)]
use std::cmp::*;
use std::collections::*;
use std::io::Write;
use std::ops::Bound::*;

#[allow(unused_macros)]
macro_rules! debug {
    ($($e:expr),*) => {
        #[cfg(debug_assertions)]
        $({
            let (e, mut err) = (stringify!($e), std::io::stderr());
            writeln!(err, "{} = {:?}", e, $e).unwrap()
        })*
    };
}

fn main() {
    let k = read::<i64>();
    let mut k2 = k;
    for i in 2..=2000000 {
        let g = gcd(k2, i);
        if k2 % g == 0 {
            k2 /= g;
        }
        if k2 == 1 {
            println!("{}", i);
            return;
        }
    }
    println!("{}", k2);
}

fn gcd(a: i64, b: i64) -> i64 {
    if b == 0 {
        return a;
    }
    gcd(b, a % b)
}

type Input = i64;
fn binary_search<F>(lb: Input, ub: Input, criterion: F) -> (Input, Input)
where
    F: Fn(Input) -> bool,
{
    assert_eq!(criterion(lb), true);
    assert_eq!(criterion(ub), false);
    let mut ok = lb;
    let mut ng = ub;
    while ng - ok > 1 {
        let mid = (ng + ok) / 2;
        if criterion(mid) {
            ok = mid;
        } else {
            ng = mid;
        }
    }
    (ok, ng)
}

fn read<T: std::str::FromStr>() -> T {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    s.trim().parse().ok().unwrap()
}

fn read_vec<T: std::str::FromStr>() -> Vec<T> {
    read::<String>()
        .split_whitespace()
        .map(|e| e.parse().ok().unwrap())
        .collect()
}

fn get_primes(n: i64) -> Vec<i64> {
    let mut is_prime = vec![true; n as usize + 1];
    let mut primes = Vec::new();
    is_prime[0] = false;
    is_prime[1] = false;

    for i in 2..n + 1 {
        if is_prime[i as usize] {
            primes.push(i);
            let mut j = 2 * i;
            while j <= n {
                is_prime[j as usize] = false;
                j += i;
            }
        }
    }
    primes
}

fn factorize(mut num: i64, primes: &Vec<i64>) -> std::collections::HashMap<i64, i64> {
    // max_primes >= (num)^(1/2)
    let num_org = num;
    let mut dict = std::collections::HashMap::new();
    for &p in primes.iter() {
        while num % p == 0 {
            *dict.entry(p).or_insert(0) += 1;
            num /= p;
        }
        if num == 1 {
            break;
        }
        if p * p > num_org {
            *dict.entry(num).or_insert(0) += 1;
            break;
        }
    }
    if num != 1 {
        dict.insert(num, 1);
    }
    dict
}

提出情報

コンパイルエラー

warning: type alias is never used: `Input`
  --> src/main.rs:41:1
   |
41 | type Input = i64;
   | ^^^^^^^^^^^^^^^^^
   |
   = note: `#[warn(dead_code)]` on by default

warning: function is never used: `binary_search`
  --> src/main.rs:42:4
   |
42 | fn binary_search<F>(lb: Input, ub: Input, criterion: F) -> (Input, Input)
   |    ^^^^^^^^^^^^^

warning: function is never used: `read_vec`
  --> src/main.rs:67:4
   |
67 | fn read_vec<T: std::str::FromStr>() -> Vec<T> {
   |    ^^^^^^^^

warning: function is never used: `get_primes`
  --> src/main.rs:74:4
   |
74 | fn get_primes(n: i64) -> Vec<i64> {
   |    ^^^^^^^^^^

warning: function is never used: `factorize`
  --> src/main.rs:93:4
   |
93 | fn factorize(mut num: i64, primes: &Vec<i64>) -> std::collections::HashMap<i64, i64> {
   |    ^^^^^^^^^

ジャッジ結果